There are two big types of shad: the Alosa alosa and the Alosa fallax fallax.
The Alosa fallax fallax and the Alosa alosa differ mainly by the size and
the scales.
They both have silversides and stomachs.
The Alosa alosa can measure between 30 and 70 cms and it can weigh up to
5kg for the female.
It has a blue-grey back and 5 to 9 black spots on the side.
The Alosa fallax fallax can measure as for her between 35 and 45 cms and
can weigh up to 2 kg for the female.
It has a green-blue to grey back and 2 to 3 black spots on the front.
Offshore, the Alosa fallax fallax stays near coasts contrary to the Alosa
alosa and they eat invertebrates, shellfish and little fish and do not eat in fresh water.
Both types of shad are present within the watershed of the Charente.
We know that front of migration of shad can vary according to the hydroclimatic
conditions at the time of the ascent of fishes.
The eel is a fish which in the collective imagination arouses both attraction and aversion …
Attraction because of its uncommon aspect for a fish and an aversionbecause of its body which
looks like a snake.
The eel has a thick and sticky skin at the grown-up stage.
This strange fish lives in very varied aquatic habitats: from littoral
ponds to swamps and trout rivers of pre-mountain.
The eel reproduces in Sargasso Sea, east of the Bahamas, then the larvae
are pulled by the Gulf Stream towards the French coasts and so migrate to fresh
water.
The eel is the object of extensive fishing at the stage of larvae today.
In our regions, the larva of eel is considered a very fine and delicious
dish and is consequently sold a very expensive price.
This species is thus a victim of its success and is endangered by poaching.
At the moment, the eel is present in the whole watershed of the Charente.
However, we note a regression and this very resistant fish has become rare and
absent in the whole Atlantic front.
According to studies carried out by the « EPTB fleuve Charente »,
the main causes of this regression are:
- the physical obstacles to the migration (problems of accessibility to
the wetlands)
- the pressure of fishing (poaching)
- a perturbed quality of waters (industrial and agricultural pollutions)
- the regression of the wetlands
- predation (by the cormorant)
Lampreys are not fish in the strict sense of the term.
They do not possess either jaws, or scales, or fins, or an osseous spine.
This strange fish which is similar in shape to the eel, has a sort of circular
mouth with many teeth, that works as a suction cup.
There are two types of lamprey: the sea lamprey and the river lamprey.
The sea lamprey measures between 60 and 80 cms, can weigh up to 900 g and
its life span is about 8 years.
The river lamprey measures between 25 and 35 cms, can weigh up to
60 g and has a life span of 7 years.
What differentiates these two types of lamprey is also the number of "teeth".
Within the watershed of the Charente, lampreys are especially threatened
by dams and diverse pollutions.
We know that this sensibility is increased by a relatively long
embryonic phase.
